Gene therapy holds promise for treatment of a variety of diseases. However, transfer techniques using biological vectors is not without serious problems. Therefore, gene delivery using non-viral approach is highly preferable due to convenience of delivery, ease of manufacturing, cost effectiveness, and biocompatibility. However, these techniques are limited by low transfection efficiency. To address this problem, we have developed nano-sized calcium phosphate particles, NanoCaPs, as a novel delivery system for plasmid DNA transfection. We hypothesize that NanoCaPs will serve as a superior transfection system because the reduced crystalline dimensions will result in increased surface-active DNA binding and greater cellular uptake and enhanced transfection efficiency. This elegant non-viral gene delivery system could be used alone or incorporated into synthetic or natural polymers to deliver genes in a sustained manner. [unreadable] [unreadable] To prove our hypothesis we propose to synthesize NanoCaPs incorporated in a biodegradable fibrin matrix to enhance both the in vitro and in vivo transfection efficiency of plasmid DNA (pDNA). This technology will increase the uptake and expression of marker genes (luciferase and/or beta-galactosidase) as well as therapeutic transfectents. A dentin regenerative therapy model will be used to locally administer plasmid DNA vectors encoding rat bone morphogenetic protein-7 (BMP-7) in a composite nano-sized calcium phosphate carrier matrix to enhance dentin regeneration. Our preliminary in vitro and in vivo data is in excellent agreement with our objective to design and develop this efficient plasmid gene therapy system. These results suggest the potential successful application of our approach for dentin regeneration. [unreadable] [unreadable] The present study will provide a concrete foundation for conducting further applied and basic science research related to dentin plasmid gene therapy and will also provide a model to study the biology for dentin repair and regeneration. The specific aims have been formulated to provide solutions to fundamental questions related to in vitro and in vivo pDNA transfection efficiency and the specific application of the pDNA bound NanoCaPs embedded in a fibrin matrix for dentin therapy thus providing key information currently missing. [unreadable] [unreadable]